1. Field of the Invention
The present general inventive concept relates to a developing apparatus, an imaging unit, and an image forming apparatus.
2. Description of the Related Art
An electrophotographic image forming apparatus forms an image by forming an electrostatic latent image on an outer circumferential surface of a photosensitive drum that is uniformly charged and visualizing the electrostatic latent image using toner. The electrophotographic image forming apparatus is used for digital type printers or copiers. For example, a binary developer formed of toner and carrier is used for the image forming apparatus. A toner image is formed by adhering the toner, that is frictionally charged by a mixing unit installed in the developing apparatus, to the electrostatic latent image formed on the outer circumferential surface of the photosensitive drum.
The developing apparatus of the image forming apparatus configured as above generally includes a plurality of developer transfer member that mixes and transfers the developer formed of toner and carrier in a development container to which the toner is supplied. The developer transfer member is provided with a spiral wing member at a rotation shaft to mix and transfer the developer. Also, both end portions of the rotation shaft of the developer transfer member are rotatably supported on the development container via a bearing portion.
When the developer intrudes into the bearing portion as the developer transfer member circulates the developer in the development container, torque of the bearing portion increase so that the bearing portion may be overheated. As a result, the toner is melted and closely contacts the bearing portion or granulated in the vicinity of the bearing portion. Accordingly, the bearing portion is locked so as not to be able to form an image. Also, the generated granulates are accumulated on a layer restriction portion to generate a vertical line on an image. Furthermore, a defect such as a spot is generated on an image so that reliability/durability of the developing apparatus may be deteriorated